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Switches in Parallel

We continue our series on copper tape circuits with a parallel circuit. With a parallel circuit, the LED lights even if you only have one switch closed. I'm using a one-inch faster, which are easier to find, if less graceful looking, than the smaller fasteners used for the knob switch.

Step 1: Tools and Materials

Scissors or Craft Knife

Slug and snail tape cut into quarter inch widths

Brass fasteners x2

Card stock or index cards

Step 2: Sketch Your Circuit

I like to sketch out the circuit first. This gives me an idea of how all the components fit together. It also allows me to walk through the circuit, sometimes I will actually trace the circuit with my finger.

Step 3: Cover Your Traces

I apply copper tape even to places where there is a component. You can also leave the component spaces open.

Step 4: Cut Out Space for Components

Using a scissor blade or the craft knife blade, cut open the spaces where your components will be. Lift the tape off with a blade corner or just use your fingers.

Step 5: Connect Components

Apply copper tape to the LED and battery leads, securing them to the copper traces. Remember that the positive ends of the battery and LED should meet. The side of the battery with the plus sign should connect directly to the long lead of the LED.

Step 6: Add the Switches

Make a starter hole with your knife, scissors, or even a paper clip. Push the fastener through the hole and flatten the lengths so they make contact with the adjacent copper tape.

Step 7: Check Your Connections

Complete the circuit and see that your LED lights. Sometimes all you need to do is tighten the connections if the LED doesn't light at first.

Step 8: Vexations, Meditations, and Variations

I'm still not happy about the fasteners as switches. As you saw on the video, the switches stick on the copper. The connections get a little weak, too. Also, I'm still using the wonderful coin cell battery with the built in leads, something that most people don't have access to. In successive Instructables, I will use off the shelf batteries.

All in all, though, you get an idea that a positive output can result from one or more positive inputs, the concept of an OR gate.

You can expand this by adding additional switches or additional LEDs. What happens when you increase the number of LEDs? What if you connected an AND gate to an OR gate?

I'd also like to try a different mounting surface, say, a thin, rigid, easily-cuttable plastic.